770 NEW YORK STATE MUSEUM 



infested in the spring of 1900 and abundantly so the following 

 autumn. This is certainly not a very bad showing for this oil. 



Crude petroleum, undiluted Titusville oil. The disastrous results 

 obtained with this substance last year acted as a check to more 

 extensive experiments this season. It was decided to test in a 

 small way some of the crude petroleum received from Titusville 

 Pa., because, according to certain published accounts, it would 

 not harm the trees. A description of its physical properties is 

 given on p. 762. Three trees were sprayed with this substance. 

 Tree 20, a Bartlett pear, was very badly infested with 

 the scale in 1900, and it was selected among others, for treat- 

 ment that spring with undiluted kerosene. It was in a very 

 bad state to begin with, and last October even the suckers from 

 this tree appeared to be in an unhealthy condition. It was 

 sprayed Ap. 11, 1901, with this crude petroleum. It developed 

 no leaves the present season, and it was probably nearly dead 

 before the petroleum was applied. Tree 116 was a Lombard 

 plum which was very badly infested with the San Jose" scale, 

 but, as the infestation was comparatively recent, and as the tree 

 had received no previous application of an insecticide, it was a 

 very good subject to experiment on. The oil was sprayed on the 

 tree rather liberally Ap. 11, and July 3 it was seen that several 

 limbs were seriously injured and dying, and that some of the 

 others gave indications of feebleness. Aug. 9, this tree was 

 dead, the result, undoubtedly, of the application of the oil. Less 

 oil would probably have been less injurious, but the fact remains 

 that this so called safe oil is not necessarily so. The third tree 

 w T as Crawford peach, which was very badly infested with 

 San Jose" scale, and, like the preceding, it had not been treated 

 with any insecticide. The scales were so abundant as literally 

 to cover most of the trunk and the larger limbs, and in some 

 places they appeared to be two or three deep. This tree devel- 

 oped no leaves, and it was probably very seriously injured by 

 the scale infestation. Its death can hardly be attributed to the 

 application of the oil. 



Good's whale oil soap no. 3 and 10 fo petroleum. The Standard oil 

 was used in these experiments. There were 12 trees treated 



